1601891515591 has 2 divisors, whose sum is σ = 1601891515592. Its totient is φ = 1601891515590.

The previous prime is 1601891515579. The next prime is 1601891515621. The reversal of 1601891515591 is 1955151981061.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1601891515591 - 2⁵ = 1601891515559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1601891515391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800945757795 + 800945757796.

It is an arithmetic number, because the mean of its divisors is an integer number (800945757796).

Almost surely, 2^{1601891515591} is an apocalyptic number.

1601891515591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1601891515591 is an equidigital number, since it uses as much as digits as its factorization.

1601891515591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 486000, while the sum is 52.

The spelling of 1601891515591 in words is "one trillion, six hundred one billion, eight hundred ninety-one million, five hundred fifteen thousand, five hundred ninety-one".